With the summer approaching, I am making some experiments trying to cool my pc as much as possible while keeping it quiet. Now, airflow in the case is made by 2 fans: the intake fan, a Papst 4412 F/2GLL, pulls air inside the case from the front, the exhaust fan, a Antec Tricool coming with the SLK3000B, pushes air out to the back; in addition, the psu fan pulls air from the top of the motherboard through the psu to the back.
Since I bought a second Papst 4412 F/2GLL, I tried positioning this fan in different locations to see which one conributes the best to the cooling. One of these is the back of the case, in the bottom, where there would be additional cards: it pushes air out of the case through the back slots.

The main problem of the Antec SLK3000B case is it converts hard disk vibrations to noise, and this is the most annoying noise coming from my pc when the fans are set at the lowest speed. In the SLK3000B the hard disks lay in a cage with grommets that are supposed to dampen the vibrations of the 7200 and more rpm hard disks.
The trend spreading amongst silencing modders is to suspend the hard disks in the air to avoid contact between the case and the hard disks.